CT angiography after face transplantation. Recipient’s left lingual artery was ligated, but the portion distal to the ligation (rectangular area) was still enhanced via blood flow from the contralateral side (arrow).
(Brigham and Women's Hospital)

As full face transplantation continues to become a more viable option for patients with severe facial disfigurations, doctors have learned more and more about the intricacies of this novel procedure.

Now, for the first time ever, researchers have discovered that in the months following the procedure, the blood vessels in the faces of transplant recipients are actually able to reorganize themselves.

Detailed in a study presented at the annual meeting of the Radiological Society of North America (RSNA), this “vascular reorganization” provides physicians with a better understanding of the biologic processes that occur during full face transplantation.

Still a relatively new procedure, full face transplants have only been available to patients within the past two years – the first successful operation in the United States was performed at Brigham and Women’s Hospital in Boston in 2011. Since then, hospital specialists have performed face transplantations on three additional patients.

According to study author Dr. Frank Rybicki, the most important element required for a successful face transplantation is an adequate blood supply from the donor. During the procedure, surgeons must connect the patient’s major arteries and veins to those located in to the donor face – also called the facial allograft – in order to provide healthy circulation.

However, new blood vessel networks must development in the transplanted tissue in order for the surgery to succeed, and up until now, not much has been known about these vascular changes.

“We have to have the tissue perfuse, which is this connection of blood vessels from the patient to the cadaver,” Rybicki, director of the Applied Imaging Science Laboratory at Brigham and Women’s Hospital, told FoxNews.com. “Now that we’re a year out from the first patients [who had this procedure done], for the first time we can see those connections and map out the perfusion. And that reorganization of the blood vessels is very biologically interesting.”

For the study, Rybicki and his colleagues analyzed the blood vessels of three transplant patients one year after their surgeries. The researchers used a special imaging technique, known as 320-detector row dynamic computed tomography angiography (CTA) to map out the patients’ facial allografts.

Through this imaging, they found that existing vessels in both the donor and recipient’s tissue had morphed and made new connections with each other – a process known as collateralization. Rybicki said this showed that there is an extensive vascular reorganization that occurs “in concert” with the larger vessels that are initially connected during surgery.

“For example, when you do a face transplant, you have to sever both vessels on each side of the tongue,” Rybicki said. “But…there is such a strong genetic predilection to keep the tongue perfused, that even though we have to make these operative decisions – severing the lingual artery – the body finds a way to re-perfuse it.”

Rybicki said this study reveals just how critical the face has become in regards to the human body, noting that distinctive facial features have become so essential in how we identify ourselves and others.

“It means we’re hardwired to protect our face and our tongue in a very profound way,” Rybicki said. “Even when you put tissue back on there, the body knows it and the body reorganized. We still use immunosuppressant drugs, but the blood vessels know to reorganize in a certain way.”

Notably, the researchers found that most of the new blood vessel networks came from vessels farther back in the head and toward the ears. These findings could ultimately help physicians to create better assessment protocols, helping them determine which candidates are best suited for full face transplantation and which patients may have severe complications.

“There are an enormous number of patients that have severe facial injuries; we just don’t see them because they don’t come out of their house,” Rybicki said. “The implications of this study are if those patients have the right vessels we know need to be reorganized, we can work with them.”